EP1555101A1 - Wire saw device - Google Patents

Abstract

The device has units (34) constituted of sliding and guiding units (32), to effect a relative transversal displacement between an assembly of sawn wafers (30) and a set of wire saws (15) along a cutting direction (Y), so that the saws cut and separate the sawn wafers in the device. The sawn and cut wafers are directly introduced into a wafer receiving receptacle (41) provided with separation units (43).

Description

The present invention relates to a wire sawing device comprising a frame and at least one sheet of wire stretched between at least two guide-son cylinders whose axes are substantially parallel and maintained in position by the wire guide cylinders which define the gap between the threads of said web of threads, therefore the thickness of sawn slices separated from each other by interstices, the wires being capable of moving according to a reciprocating or continuous movement against at least one fixed workpiece on a support table via at least one support, means being intended to effect a relative advance movement between the workpiece and the sheet of threads in a direction of advance.

Wire sawing devices of the aforementioned type with wire displacement of the sheet of thread or piece to be sawn are already known, especially in the electronic components industry of ferrites, quartz and silicas, for obtaining thin slices of materials such as poly silicon or monocrystalline or new materials such as GaAs, InP, GGG or also quartz, synthetic sapphire, ceramic materials. The high price of these materials makes wire sawing more attractive compared to other techniques such as diamond sawing.

In known devices, the sawing zone consists of a set at least two cylinders placed parallel. These cylinders, called son-guides, are engraved with grooves defining the interval between the threads of the tablecloth, either the thickness of the slices. The piece to be sawn is fixed on a support table which moves perpendicular to the sheet of threads. The speed of movement defines the cutting speed. The renewal of the wire, as well as the control of its tension is done in a part called the wire management area outside the zone sawing itself. The agent that will govern the cutting is either an abrasive fixed on the wire, a free abrasive brought as a slip. The thread acts only as carrier. When cutting in thin slices of the workpiece, the tensioned wire is both guided and towed by the wire guide cylinders.

When the sawing of the slices is finished, the piece to be sawed will be in the form of a set of parallel slices separated from each other by the kerf or sawdust but attached to their base by a heel partially cut and forming part of a temporary support placed between the sawing piece and a mounting bracket. For the dismantling of this set, he will completely take out the son of the sheet of threads through the interstices sawing to be able to remove the sawed part from the sawing device. This operation is time consuming and delicate, as sawn slices can be damaged during this return. In addition, the threads of the thread could break during this operation. When the sawed piece is out of sawing device, it will then be necessary to separate the slices of their heel and the support temporary to put them in storage elements commonly called cassettes, which can prove to be a long and tedious operation.

The present invention aims to overcome the aforementioned drawbacks and the invention is characterized for this purpose by the fact that the sawing device comprises means for effecting a transverse relative displacement between the whole of the sawn slices of the piece to be sawn and the sheet of threads following a cutting direction substantially parallel to the axes of the guide-wire cylinders so that the son of the sheet of threads serve as tools for cutting the slices sawed, the amplitude of this transverse relative displacement being determined from sawn slices are separated and separated from one another and of their support.

The son of the sheet of threads are thus directly used as tools of cutting to separate the slices sawed from each other and their heel. The dismantling of sawn parts is greatly simplified since it is no longer necessary to bring out the son of the sheet of son of the sawing interstices. In addition, the sawn slices are directly available without cutting outside the sawing device. Acquisition and use cutting equipment then becomes superfluous, which makes it possible to significantly reduce installation costs and manufacturing time.

According to a preferred embodiment, said means for performing a transverse relative displacement are constituted by guide elements and sliding allowing a relative translation of the workpiece or parts to be sawed by compared to the web of threads.

These characteristics allow a particularly reliable construction and uncomplicated.

Favorably, the sawing device comprises at least one receiving part removably mounted on the device and arranged to receive slices sawed and separated after cutting.

The removal of the sawn slices is thus particularly practical and easy.

Advantageously, the sawing device comprises means for maintained to maintain, during and after sawing and cutting, sawn slices substantially parallel to each other and so that the width sawing gaps are substantially preserved.

These holding means are further favorably arranged in the receiving organ.

Thanks to these characteristics, sawn slices are directly in cassette in the sawing device. It is therefore no longer necessary to separate from each other. Putting in storage element long and tedious, as well as the significant risks of breakage are completely avoided.

For many applications, sawn slices or wafers are of very small thickness compared to the diameter of the workpiece. The slices sawn products therefore have considerable flexibility and can flex and bend for contact with neighboring slices. These deflections are harmful for the precision and flatness of the cut and can induce ripples, streaks and undesirable irregularities on the surface of sawn slices. These irregularities, even a few micrometers are enough to render unusable the slices for certain applications, such as silicon for the solar industry and semiconductors. The deformations of the slices can even induce microcassures and breaks, especially near the fixing of the slices to their support.

In addition, variations in the position of slices and in the width of sawing interstices are likely to influence intake and distribution abrasive in the interstices of sawnwood, which in turn leads to variations in slice thickness, sawing speed and yarn wear, therefore a further increase in the irregularities of the surface of the slices obtained, as well as an increased risk of wire breakage.

If the wire breaks, it is very difficult, if not impossible, to repair the wire and to make it penetrate again between slices that touch or whose sawing gap has become very low. It is then necessary to throw the sawing piece in case of wire breakage and start sawing again with a new piece, which causes a considerable loss of materials often very expensive and sawing time.

With the aforementioned holding means all these major disadvantages can be avoided simultaneously, while benefiting from the benefits of in an automatic cassette in the sawing device.

Advantageously, the holding means comprise elements separation devices intended to be introduced at least partially into the interstices sawn between the slices to maintain these, these elements of separation being mounted on at least one support.

Thanks to these characteristics, the gap between the slices can be maintained very precisely, even in the case of external forces acting on the slices under sawing.

Favorably, the separation elements are constituted by wires, strips, boards or walls of adequate thickness to be able to be introduced into said sawing gaps.

The maintenance and the separation of the sawn slices are thus made of simple and effective way.

According to an advantageous embodiment, said at least one support is arranged in at least one tray mounted on said frame.

These features allow for easy integration of sawed in a production line.

Another embodiment is characterized by the fact that the means of maintenance consist of a U-shaped frame whose branches are intended to be applied laterally against slices sawed.

Such a frame can be mounted and removed by lateral displacement during sawing of the room. This mode of execution is therefore particularly useful in case of rupture sawing wire. During repair, the gaps between the slices can be kept constant by this device and the wire can be easily replaced and reintroduced between the slices after repair. In addition, the frame can also be used for the transport of the workpiece after sawing and side cutting of slices.

La figure 1 est une vue de face d'un premier mode d'exécution de l'invention.

Les figures 2a et 2d sont des vues latérales partielles du premier mode d'exécution avant et après le découpage des tranches de leur talon.

Les figures 2b et 2c montrent des particularités de la figure 2a lors du découpage et la figure 2e représente ces particularités après le découpage.

La figure 3 est une vue de détail d'une variante du premier mode d'exécution.

Les figures 4a et 4d sont des vues latérales partielles d'un second mode d'exécution avant et après le découpage du talon.

Les figures 4b et 4c montrent des particularités de la figure 4a lors du découpage et la figure 4e représente ces particularités après le découpage.

Les figures 5a et 5b illustrent une variante du mode d'exécution précédent.

La figure 6 est une vue de face partielle d'une autre variante.

La figure 7 est une vue partielle en perspective d'un troisième mode d'exécution.

Other advantages emerge from the features expressed in the dependent claims and from the following description explaining the invention in more detail with the aid of drawings which show schematically and by way of example several embodiments and variants.

Figure 1 is a front view of a first embodiment of the invention.

Figures 2a and 2d are partial side views of the first embodiment before and after cutting the slices of their heel.

Figures 2b and 2c show features of Figure 2a during cutting and Figure 2e shows these features after cutting.

Figure 3 is a detail view of a variant of the first embodiment.

Figures 4a and 4d are partial side views of a second embodiment before and after cutting the heel.

Figures 4b and 4c show features of Figure 4a during cutting and Figure 4e shows these features after cutting.

Figures 5a and 5b illustrate a variant of the previous embodiment.

Figure 6 is a partial front view of another variant.

Figure 7 is a partial perspective view of a third embodiment.

With reference to FIG. 1, the sawing device according to the first embodiment embodiment comprises a frame 10 and guide-son cylinders 11, 12, here in number two, mounted on this frame with their axes 13 arranged parallel, being well understood that the device could have more than two guide-wire cylinders.

The yarn 14 is unwound from a delivery reel, not shown, and then wound around the wire guide cylinders according to any winding mode possible to form at least one web of parallel threads in a sawing zone. The thread is then recovered in a suitable device not shown, such as a coil receiver or a recycling bin.

One, two or more pieces to be sawed 17, such as ingots in one hard material, are mounted on a support table 18.

This support table 18 can be moved vertically in one direction in advance Z through a column 21 and a motor 20 to support the or pieces to be sawed 17 against the sheet of threads 15.

The periphery of the wire guide rolls 11, 12 is etched with grooves which define the interval between the adjacent son of the sheet of son 15, so the thickness sawn slices. These are separated from each other by slits or interstices of sawing.

The wire 14 is stretched and both guided and pulled by the wire guide cylinders for move alternately back and forth or continuously. This thread is favorably constituted of spring steel with a diameter between 0.1 and 0.2 mm to saw blocks of hard materials or composition more particular, such as silicon, ceramic, compounds of the elements of groups III-V and II-VI, GGG (Gadolinium-Gallium Garnet), sapphire, etc., in increments of 0.1 to About 5 mm thick. The abrasive agent is a commercial product and can be diamond, silicon carbide. alumina, etc., in a form attached to the wire or free form suspended in a liquid that serves as a carrier for particles of the abrasive.

When sawing and slicing operations are finished, the sawn slices are recovered in a receiving tray 25 disposed on a support 26 secured to the frame 10.

With reference to FIGS. 2a to 2e, the workpiece (s) 17 are fixed by collage on a temporary support 28 which can be made of glass or material synthetic material and this temporary support is fixed by gluing on a support of mounting 29, for example steel. The latter is mounted on the support table 18 thanks to guiding and sliding elements 32 making it possible to retain the mounting bracket 29 on the support table 1 in the vertical direction Z and allowing a relative translation between the support table 18 and the support of assembly 29 in a Y direction, parallel to the axes 13 of the wire guide cylinders 10, 11 and perpendicular to the son of the sheet of son 15, so a translation relative to the piece (s) to be sawed and the layer of yarns in the Y direction.

The sawing of the pieces 17 in slices 30 is performed thanks to a movement relative to the workpieces 17 and the web of threads 15 in the direction of advance Z. This sawing motion is continued until the threads of the thread 15 enter the temporary support 28.

Before the present invention, it was then necessary to perform a reversing movement in the Z direction in the opposite direction to disengage the web of threads 15 of the interstices 31 sawing between the slices. Only then it was possible to remove the sawing piece (s) 17 with the sawn slices 30 of the sawing device. It was then necessary to cut or cut slices 30 from each other and their heel constituted by a portion of the temporary support 28 by means of a suitable cutting tool, such as a diamond disc.

According to the present invention, these operations are avoided. In According to the present invention, the sawing device comprises means 34 which make it possible to make a transverse relative displacement between all the sawn slices 30 of the workpiece 17 and the ply of threads 15 in the direction Y cutting parallel or substantially parallel audits axes 13 cylinders guide-son. The amplitude of this transverse relative displacement is determined from sawed slices 30 are detached from each other and from their temporary support 28 serving as a heel to be recovered in the tray of reception 25.

In the embodiment described, the means 34 that allow this relative displacement are constituted by the guiding and sliding 32 along the Y direction.

FIG. 2b shows in enlarged view the relative position of the support table 18 and the web of threads 15 with respect to that of the sawn slices 30 and the mounting bracket 29 before cutting or cutting off slices sawn 30.

In an intermediate position illustrated in FIG. 2c, the yarn 14 of the tablecloth of wires 15 serving as a cutting tool partially cut the slices 30 at the temporary support 28 which has moved with the mounting bracket 29 to the right with respect to the ply of threads 15 and the support table 18.

Figures 2d and 2e show the final position after cutting or complete cutting of the sawn slices 30 which rest in the tray of 25 and can therefore easily be extracted from the sawing device in this receiving tray 25.

The transverse relative displacement in the direction Y can be carried out in a different way, for example by transverse displacement of a part or the entire support table 18 or by lateral displacement of the tablecloth of threads 15 with respect to sawn slices 30.

Cutting slices sawed in the Y direction can be performed at different level, either in the temporary support 28 or in the glue between this temporary support 28 and the workpiece 17, still in the end upper part of the workpiece 17.

According to a variant illustrated in FIG. 3, the transverse relative displacement according to the cutting direction Y can be achieved through a vertical piece 35 secured to the mounting bracket 29 and to a screw 36 passing through the vertical part 35 by a threaded bore and bearing on the support table 18.

By rotation of the screw 36, either manually or motorized by a motor not shown, the mounting bracket 29 and the workpiece 17 are moved to the right in FIG. 3 in the direction Y and the threads of the ply of threads 15 cutting tools cut through the sawed slices 30 at the level of the temporary support 28 to separate them completely from each other.

This transversal displacement can also be realized by all types mechanical, electrical, hydraulic or mechanical drive members tires.

In the embodiment illustrated in FIGS. 4a to 4e, the same elements are designated by numbers identical to those of Figures 2a to 2e. This mode in particular is characterized by holding means 40 to maintain slices 30 partially or fully sawn substantially parallel to each other and so that the width of the interstices of sawing 31 between the slices 30 is kept substantially constant during the sawing slices and during and after cutting or crosscutting subsequent slices 30 of their mounting bracket 29.

These holding means 40 are in the case of Figures 4a to 4c mounted on the frame 10 of the sawing device 10 and comprise a tank 41 whose bottom and / or the walls may be perforated or provided with a flow so that the sawing liquid and abrasive can be removed from the tank. This tray is maintained thanks to fastening elements 42 on the frame 10 and provided with elements of separation 43 intended to be introduced into the sawing gaps 31 between the sawn slices 30 to maintain exactly the gap between them.

The separation elements 43 are in this embodiment constituted by a series of son 44 stretched on frames 45. The embodiment shown has two frames 45 superimposed, but any other number of frames from 1 to 5 can be mounted in the tank 41.

Thus, the sawing can be carried out up to the temporary support 28 (FIG. 4a), while the sawn slices 30 are held with a regular gap, this which ensures high product quality without ripples, streaks and irregularities.

In addition, sawn slices are already separated from one another, which facilitates further processing and conditioning.

When cutting or subsequent cutting (Figures 4b, 4c), the support 29, the sawn slices 30 and the frames 45 with their threads separation 44 are moved transversely in the Y direction. Frames 45 thus have a degree of freedom with respect to the tray 41 and can be displaced laterally with respect to this tray, as can be seen in FIGS. 4b, 4c and 4e.

At the end of cutting or bucking (Figures 4d and 4e), the slices sawed 30 are kept separate from one another in the tray 41 which serves transport cassette allowing the easy removal of all sawn slices 30, without it being necessary to take the yarns out of the sheet of yarn Sawing gaps 31, as has been the case before the present invention.

According to a variant illustrated in FIGS. 5a and 5b, the separation elements 43 as separation son 44 are supported by bands 75 having an accordion folded structure. In the position illustrated in the figure 5a, the sawed slices 30 are separated by interstices 31 of sawing a narrow width. After complete sawing, sawn slices can be removed from each other thanks to the accordion-folded structure of the strips 75 (FIG. 5b) to obtain much wider separation gaps 31a. Thus, sawn slices can no longer stick to each other and can be washed and easily treated. They can also be easily decanted in standardized storage cassettes. This variant is therefore characterized by spacing means 74 of the separating elements 43 allowing spacing of sawn slices.

According to another favorable variant illustrated in FIG. 6, two drawers 51, 52 can be slidably housed in a tray 50 attached to the frame 10.

Each of the drawers contains holding means 40 for the slices of one or other of the pieces to be sawed.

The bottom and the side walls of these drawers 51, 52 may be perforated for the flow of sawing liquid. The latter can be retained in the tray 50 and discharged by a flow 54 with a valve 55.

The holding means 40 also comprise elements of separation 43 to be introduced into the sawing gaps. These separating elements 43 may consist of horizontal wires, oblique and / or diagonal stretched on one, two or more frames 56. The threads obliques 44a may thus constitute two sheets of cross threads.

Separation elements may also consist of vertical walls or strips attached to the side walls of the drawers. After sawing and bucking, the drawers 51, with the sawn slices of each of the ingots can be removed from the sawing device in the manner of cassettes.

Another embodiment of holding means 40 illustrated in FIG. 7 comprises a U-shaped frame 60. The longitudinal branches 61 of this frame are intended to be applied laterally against the sawn slices 30 of the piece sawing 17 by means of elastic pieces 62. The force of application and maintenance can be obtained by means of a pneumatic device 63 comprising a inlet duct 64 and internal ducts to inflate parts 62. The force of application may also be obtained by other means, such as a mechanical clamping of the longitudinal branches 61 the one to the other by mechanical, pneumatic or hydraulic control.

This frame 60 can be put in place during sawing to maintain the parallel sawn slices. When final slicing or slicing of slices sawed, the slices 30 are clamped and can be quickly removed from the sawing device by means of the handle 66. It will also be possible to use two or more frames 60 superimposed and applied as and when sawing progress.

It is understood that the embodiments described above do not are not limiting in nature and may be modified desirable within the framework as defined by claim 1. In particular, one, two or more support tables 18 can support one or more pieces to be sawed 17.

The relative transverse displacement can be realized differently, for example by moving all the suspended elements or by moving the sheet of threads.

The tray receiving tray and the separating elements of slices may have any other construction, for example in the form of cassettes, each adapted to receive the slices of a sawed part.

Claims (15)

A wire sawing device comprising a frame (10) and at least one ply of wires (15) stretched between at least two wire guide cylinders (11, 12) whose axes are substantially parallel and held in position by the guide cylinders son (11, 12) which define the gap between the son of said sheet of son, and therefore the thickness of the slices (30) sawed separated from each other by sawing gaps (31), the son being likely to moving in reciprocating or continuous movement against at least one workpiece (17) fixed on a support table (18) by means of at least one support (28, 29), means (20, 21) being provided for effecting a relative advance movement between the workpiece (17) and the ply of threads (15) in a direction of advance (Z), characterized in that the sawing device comprises means (34) ) to effect transverse relative displacement between all the sawn slices (30) the workpiece (17) and the ply of threads (15) in a cutting direction (Y) substantially parallel to said axes (13) of the guidewire cylinders so that the son of the ply of threads serve as tools for cutting the sawn slices (30), the amplitude of this transverse relative displacement being determined so that the sawn slices (30) are detached and separated from each other and their support (28, 29). Device according to claim 1, characterized in that said means (34) for effecting a transverse relative displacement are constituted by guide and sliding elements (32) allowing relative translation of the workpiece (s) (17) by relative to the web of threads (15). Device according to claim 2, characterized in that the guiding and sliding elements (32) are arranged between the support table (18) and the at least one support (28, 29) or in the support table (18). Device according to claim 2 or 3, characterized in that the guiding and sliding elements (32) are driven manually (35, 36) or by any mechanical, electrical, hydraulic or pneumatic. Device according to one of the preceding claims, characterized in that it comprises at least one receiving member (25) removably mounted on the device and arranged to receive the sawed slices (30) and separated after cutting . Device according to one of the preceding claims, characterized in that it comprises holding means (40) arranged to maintain, during and after sawing and cutting, the slices (30) sawed substantially parallel to each other and so that the width of the sawing gaps (24) is substantially maintained. Device according to claims 5 and 6, characterized in that the holding means (40) are arranged in the receiving member (25). Sawing device according to claim 6 or 7, characterized in that the holding means (40) comprise separating elements (43) intended to be introduced at least partially into the sawing gaps (31) between the slices (30). ) to maintain the latter, these separating elements being mounted on at least one support (45, 56). Sawing device according to claim 8, characterized in that the separating elements consist of wires (44), strips, strips or walls of suitable thickness to be introduced into said sawing gaps (31). ). Device according to claim 8 or 9, characterized in that it comprises spacing means (74) separating elements (43) for spacing the sawn slices. Device according to claims 9 and 10, characterized in that the separating means (74) consist of strips (75) having an accordion-folded structure and capable of supporting the separating elements (43) formed by wires ( 44). Sawing device according to claim 8 or 9, characterized in that said at least one support (45, 56) is arranged in at least one tray (41, 50) mounted on said frame (10). Sawing device according to claim 12, characterized in that it comprises at least two supports (56) arranged in at least two drawers (51, 52) slidably mounted in the tray (50). Device according to one of Claims 9, 12 or 13, characterized in that the threads (44, 44a) are stretched on the support (45, 56) in horizontal and / or oblique directions and / or to form webs crossed threads. Sawing device according to Claim 6, characterized in that the holding means consist of a U-shaped frame (60) whose longitudinal legs (61) are intended to be applied laterally against the sawn edges (30). .

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